A family of five closely relating enzymes have been linked to fibrotic disease and to metastatic cancer. The enzymes are related to lysyl oxidase (LOX), the first family member to be described and four closely related enzymes, LOX-like1 (LOXL1), LOXL2, LOXL3, and LOXL4 (Kagan H. M. and Li W., Lysyl oxidase: properties, specificity, and biological roles inside and outside of the cell. J Cell Biochem 2003; 88: 660-672). Lysyl oxidase isoenzymes are copper-dependent amine oxidases which initiate the covalent cross-linking of collagen and elastin. A major function of lysyl oxidase isoenzymes is to facilitate the cross-linking of collagen and elastin by the oxidative deamination of lysine and hydroxylysine amino acid side chains to aldehydes which spontaneously react with neighbouring residues. The resulting cross-linked strands contribute to extracellular matrix (ECM) stability. Lysyl oxidase activity is essential to maintain the tensile and elastic features of connective tissues of skeletal, pulmonary, and cardiovascular systems, among others. The biosynthesis of LOX is well understood; the protein is synthesized as a pre-proLOX that undergoes a series of post-translational modifications to yield a 50 kDa pro-enzyme which is secreted into the extracellular environment. For LOX and LOXL1 proteolysis by bone morphogenetic protein-1 (BMP-1) and other procollagen C-proteinases releases the mature and active form. LOXL2, LOXL3 and LOXL4 contain scavenger receptor cysteine-rich protein domains and are directly secreted as active forms.
Lysyl oxidase isoenzymes belong to a larger group of amine oxidases which include flavin-dependent and copper-dependent oxidases which are described by the nature of the catalytic co-factor. Flavin-dependent enzymes include monoamine oxidase-A (MAO-A), MAO-B, polyamine oxidase and lysine demethylase (LSD1), and the copper-dependent enzymes include semicarbazide sensitive amine oxidase (vascular adhesion protein-1, SSAO/VAP-1), retinal amine oxidase, diamine oxidase and the lysyl oxidase isoenzymes. The copper-dependent amine oxidases have a second co-factor which varies slightly from enzyme to enzyme. In SSAO/VAP-1 it is an oxidized tyrosine residue (TPQ, oxidized to a quinone), whereas in the lysyl oxidase isoenzymes the TPQ has been further processed by addition of a neighboring lysine residue (to form LTQ); see Kagan, H. M. and Li, W., Lysyl oxidase: Properties, specificity, and biological roles inside and outside of the cell. J Cell Biochem 2003; 88: 660-672.
Since lysyl oxidase isoenzymes exhibit different in vivo expression patterns it is likely that specific isoenzymes will have specific biological roles. Catalytically active forms of LOX have been identified in the cytosolic and nuclear compartments which suggest the existence of undefined roles of LOX in cellular homeostasis. Significant research is currently underway to define these roles. LOX itself, for example, plays a major role in epithelial-to-mesenchymal transition (EMT), cell migration, adhesion, transformation and gene regulation. Different patterns of LOX expression/activity have been associated with distinct pathological processes including fibrotic diseases, Alzheimer's disease and other neurodegenerative processes, as well as tumour progression and metastasis. See, for example, Woznick, A. R., et al. Lysyl oxidase expression in bronchogenic carcinoma. Am J Surg 2005; 189: 297-301. Catalytically active forms of LOXL2 can be also found in the nucleus (J Biol Chem. 2013; 288: 30000-30008) and can deaminate lysine 4 in histone H3 (Mol Cell 2012 46: 369-376).
Directed replacement of dead or damaged cells with connective tissue after injury represents a survival mechanism that is conserved throughout evolution and appears to be most pronounced in humans serving a valuable role following traumatic injury, infection or diseases. Progressive scarring can occur following more chronic and/or repeated injuries that causes impaired function to parts or all of the affected organ. A variety of causes, such as chronic infections, chronic exposure to alcohol and other toxins, autoimmune and allergic reactions or radio- and chemotherapy can all lead to fibrosis. This pathological process, therefore, can occur in almost any organ or tissue of the body and, typically, results from situations persisting for several weeks or months in which inflammation, tissue destruction and repair occur simultaneously. In this setting, fibrosis most frequently affects the lungs, liver, skin and kidneys.
Liver fibrosis occurs as a complication of haemochromatosis, Wilson's disease, alcoholism, schistosomiasis, viral hepatitis, bile duct obstruction, exposure to toxins and metabolic disorders. Liver fibrosis is characterized by the accumulation of extracellular matrix that can be distinguished qualitatively from that in normal liver. This fibrosis can progress to cirrhosis, liver failure, cancer and eventually death. This is reviewed in Kagan, H. M. Lysyl oxidase: Mechanism, regulation and relationship to liver fibrosis. Pathology-Research and Practice 1994; 190: 910-919.
Fibrotic tissues can accumulate in the heart and blood vessels as a result of hypertension, hypertensive heart disease, atherosclerosis and myocardial infarction where the accumulation of extracellular matrix or fibrotic deposition results in stiffening of the vasculature and stiffening of the cardiac tissue itself. See Lopez, B., et al. Role of lysyl oxidase in myocardial fibrosis: from basic science to clinical aspects. Am J Physiol Heart Circ Physiol 2010; 299: H1-H9.
A strong association between fibrosis and increased lysyl oxidase activity has been demonstrated. For example, in experimental hepatic fibrosis in rat (Siegel, R. C., Chen, K. H. and Acquiar, J. M, Biochemical and immunochemical study of lysyl oxidase in experimental hepatic fibrosis in the rat. Proc. Natl. Acad. Sci. USA 1978; 75: 2945-2949), in models of lung fibrosis (Counts, D. F., et al., Collagen lysyl oxidase activity in the lung decreases during bleomycin-induced lung fibrosis. J Pharmacol Exp Ther 1981; 219: 675-678) in arterial fibrosis (Kagan, H. M., Raghavan, J. and Hollander, W., Changes in aortic lysyl oxidase activity in diet-induced atherosclerosis in the rabbit. Arteriosclerosis 1981; 1: 287-291.), in dermal fibrosis (Chanoki, M., et al., Increased expression of lysyl oxidase in skin with scleroderma. Br J Dermatol 1995; 133: 710-715) and in adriamycin-induced kidney fibrosis in rat (Di Donato, A., et al., Lysyl oxidase expression and collagen cross-linking during chronic adriamycin nephropathy. Nephron 1997; 76: 192-200). Of these experimental models of human disease, the most striking increases in enzyme activity are seen in the rat model of CCl4-induced liver fibrosis. In these studies, the low level of enzyme activity in the healthy liver increased 15- to 30-fold in fibrotic livers. The rationale for the consistent and strong inhibition of fibrosis by lysyl oxidase isoenzyme blockers is that the lack of cross-linking activity renders the collagen susceptible to matrix metalloproteinases and causes degradation. Hence, any type of fibrosis should be reversed by treatment with lysyl oxidase isoenzyme inhibitors. In humans, there is also a significant association between lysyl oxidase activity measured in the plasma and liver fibrosis progression. Lysyl oxidase activity level is normally negligible in the serum of healthy subjects, but significantly increased in chronic active hepatitis and even more in cirrhosis, therefore lysyl oxidase might serve as a marker of internal fibrosis.
BAPN (β-aminopropionitrile) is a widely used, nonselective lysyl oxidase inhibitor. Since the 1960s BAPN has been used in animal studies (mainly rat, mouse and hamster) and has been efficacious in reducing collagen content in various models (eg. CCl4, bleomycin, quartz) and tissues (eg. liver, lung and dermis). See Kagan, H. M. and Li, W., Lysyl oxidase: Properties, specificity and biological roles inside and outside of the cell. J Cell Biochem 2003; 88: 660-672.
Lysyl oxidase isoenzymes are highly regulated by Hypoxia-Induced Factor 1α (HIF-1α) and TGF-β, the two most prominent growth factor that cause fibrosis (Halberg et al., Hypoxia-inducible factor 1α induces fibrosis and insulin resistance in white adipose tissue. Cell Biol 2009; 29: 4467-4483). Collagen cross linking occurs in every type of fibrosis, hence a lysyl oxidase isoenzyme inhibitor could be used in idiopathic pulmonary fibrosis, scleroderma, kidney or liver fibrosis. Lysyl oxidase isoenzymes are not only involved in the cross-linking of elastin and collagen during wound healing and fibrosis but also regulate cell movement and signal transduction. Its intracellular and intranuclear function is associated with gene regulation and can lead to tumorgenesis and tumor progression (Siddikiuzzaman, Grace, V. M and Guruvayoorappan, C., Lysyl oxidase: a potential target for cancer therapy. Inflammapharmacol 2011; 19: 117-129). Both down and upregulation of lysyl oxidase isoenzymes in tumour tissues and cancer cell lines have been described, suggesting a dual role for lysyl oxidase isoenzymes and LOX pro-peptide as a metastasis promoter gene as well as a tumour suppressor gene.
To date, an increase in lysyl oxidase isoenzymes mRNA and/or protein has been observed in breast, CNS cancer cell lines, head and neck squamous cell, prostatic, clear cell renal cell and lung carcinomas, and in melanoma and osteosarcoma cell lines. Statistically significant clinical correlations between lysyl oxidase isoenzymes expression and tumor progression have been observed in breast, head and neck squamous cell, prostatic and clear cell renal cell carcinomas. The role of lysyl oxidase isoenzymes in tumor progression has been most extensively studied in breast cancer using in vitro models of migration/invasion and in in vivo tumorgenesis and metastasis mouse models. Increased lysyl oxidase isoenzymes expression was found in hypoxic patients, and was associated with negative estrogen receptor status (ER−), decreased overall survival in ER− patients and node-negative patients who did not receive adjuvant systemic treatment, as well as shorter metastasis-free survival in ER− patients and node negative patients. Lysyl oxidase isoenzymes mRNA was demonstrated to be up-regulated in invasive and metastatic cell lines (MDA-MB-231 and Hs578T), as well as in more aggressive breast cancer cell lines and distant metastatic tissues compared with primary cancer tissues.
In head and neck squamous cell carcinomas, increased lysyl oxidase isoenzyme expression was found in association with CA-IX, a marker of hypoxia, and was associated with decreased cancer specific survival, decreased overall survival and lower metastasis-free survival. In oral squamous cell carcinoma, lysyl oxidase isoenzyme mRNA expression was upregulated compared to normal mucosa.
Gene expression profiling of gliomas identified over-expressed lysyl oxidase isoenzyme as part of a molecular signature indicative of invasion, and associated with higher-grade tumors that are strongly correlated with poor patient survival. Lysyl oxidase isoenzyme protein expression was increased in glioblastoma and astrocytoma tissues, and in invasive U343 and U251 cultured astrocytoma cells.
In tissues, lysyl oxidase isoenzyme mRNA was upregulated in prostate cancer compared to benign prostatic hypertrophy, correlated with Gleason score, and associated with both high grade and short time to recurrence (Stewart, G. D., et al., Analysis of hypoxia-associated gene expression in prostate cancer: lysyl oxidase and glucose transporter-1 expression correlate with Gleason score. Oncol Rep 2008; 20: 1561-1567).
Up-regulation of lysyl oxidase isoenzyme mRNA expression was detected in renal cell carcinoma (RCC) cell lines and tissues. Clear cell RCC also demonstrated lysyl oxidase isoenzyme up-regulation. Indeed, LOX over expression appeared preferentially in clear cell RCC compared to mixed clear and granular, granular, oxyphil, tubulopapillary and chromophobe RCC/ontocytomas. In clear cell RCC, smoking was associated with allelic imbalances at chromosome 5q23.1, where the LOX gene is localized, and may involve duplication of the gene.
SiHa cervical cancer cells demonstrated increased invasion in vitro under hypoxic/anoxic conditions; this was repressed by inhibition of extracellular catalytically active lysyl oxidase activity by treatment with BAPN as well as LOX antisense oligos, LOX antibody, LOX shRNA or an extracellular copper chelator.
The scientific and patent literature describes small molecule inhibitors of lysyl oxidase isoenzymes and antibodies of LOX and LOXL2 with therapeutic effects in animal models of fibrosis and cancer metastasis. Some known MAO inhibitors also are reported to inhibit lysyl oxidase isoenzyme (e.g., the MAO-B inhibitor Mofegiline illustrated below). This inhibitor is a member of the haloallylamine family of MAO inhibitors; the halogen in Mofegiline is fluorine. Fluoroallylamine inhibitors are described in U.S. Pat. No. 4,454,158. There are issued patents claiming fluoroallylamines and chloroallylamines, for example MDL72274 (illustrated below) as inhibitors of lysyl oxidase (U.S. Pat. Nos. 4,943,593; 4,965,288; 5,021,456; 5,059,714; 5,182,297; 5,252,608). Many of the compounds claimed in these patents are also reported to be potent MAO-B and SSAO/VAP-1 inhibitors.

Additional fluoroallylamine inhibitors are described U.S. Pat. No. 4,699,928. Other examples structurally related to Mofegiline can be found in WO 2007/120528.
WO 2009/066152 discloses a family of 3-substituted 3-haloallylamines that are inhibitors of SSAO/VAP-1 useful as treatment for a variety of indications, including inflammatory disease. None of these documents specifically disclose the fluoroallylamine compounds of formula (I) according to the present invention.
Antibodies to LOX and LOXL2 have been disclosed in US 2009/0053224 with methods to diagnostic and therapeutic applications. Anti-LOX and anti-LOXL2 antibodies can be used to identify and treat conditions such as a fibrotic condition, angiogenesis, or to prevent a transition from an epithelial cell state to a mesenchymal cell state: US 2011/0044907.